This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Factor VIII (FVIII) is a key haemostasis protein of 175 kDa, essential for blood clotting. Natural mutations in FVIII result in mild to severe Haemophilia type A, a life-threatening blood condition affecting one in 5000 of the male population (Wacey et al., 1996). The sole cure for this condition is intravenous administration of FVIII, whose membrane-bound structure has been studied by Stoilova-McPhie using electron microscopy (Parmenter and Stoilova-McPhie, 2008;Stoilova-McPhie et al., 2008). Defining the structure of membrane-bound blood coagulation Factor Va and Factor VIIIa attached to lipid nanotubes by Cryo-electron microscopy is the primary goal of this project.